This instant invention is directed to a high speed bearing for use primarily in multi-spindle automatic bar machines.
As is well known, multi-spindle automatic bar machines are used to cut or machine any number machine parts into shape. An example of such parts are set screws, locking nuts, cap screws, hex head bolts, setting gears and many others. Because of space constraints and because of the fine tolerances required for maintaining the work end of the work carrying spindle, machined bearings are used to support the spindles for rotation. These bearings have two major drawbacks. First, they require break in time, which ranges between 120 hours to 240 hours, during which the machine is run at a fraction of its normal operating speed. Secondly, they wear out after running only about eight months.
It is therefore a primary object of the instant invention to provide machine bearings for multi-spindle automatic bar machine which do not require a break-in period.
The second primary object of this invention is to provide machine bearings for multi-spindle automatic bar machines which provide a much extended life span.
Another object of the invention is a high speed bearing with superior lubricating ability.
Another object of the invention is a high speed bearing in which one of the bearing cylinder and the bearing spindles is coated with a self-lubricant.
Another object of the invention is a high speed bearing having a continuous and replenishing lubricating system over the entire bearing surface.
The instant invention is directed primarily to a multi-spindle automatic bar machine which includes a housing, a plurality of spindles each having a collet at one end, and each mounted on a rotating head carried by the housing. The rotating head is adapted to rotate the spindles through a plurality of tooling stations where various industrial elements are cut to shape.
Each spindle is formed with a bearing surface about its periphery which is supported by the rotating head. The rotating head is formed with a plurality of machine bearings about its circumference in which each of the spindle bearings are carried. Each machine bearing comprises a cylinder having a circular inner bearing surface which engages with the respective spindle bearing surface. The cylinder bearing surface is formed with a spiral groove which is separated by a spiral flat. The spiral groove, which extends across the entire cylinder bearing surface, is adapted to provide a passageway for lubricant to be delivered over the entire bearing surface.
The cylinder bearing is formed of bronze or iron, while the spindle bering surface is made of medium or high carbon steel. It is preferred that the spindle is coated with a composite coating of tungsten carbide and carbon.
The cylinder bearing includes an outer circumferential groove overlaying an inner circumferential groove and at least one hole passing through the cylinder interconnecting with the inner and outer circumferential grooves. The hole along with the inner and outer circumferential grooves provide passageways for lubricant into the cylinder. The spiral groove intersects with the hole or the inner circular groove, or both.
The spiral groove comprises a first spiral groove which spirals in a first direction and a second spiral groove which spirals in a second direction opposite to the first direction. The first and second spiral grooves extend through opposite ends of the cylinder. The first and second spiral grooves begin substantially centrally of the cylinder bearing interconnecting with the circular groove about the inner surface of the cylinder.
A high speed bearing comprising a spindle bearing surface formed about a spindle and a cylinder bearing having an inner bearing surface adapted to fit over the spindle bearing surface. A spiral groove is arranged about the cylinder bearing surface forming a flat there between. The spiral groove extends the length of the cylinder and terminates through its end surfaces. A lubricant supply arrangement is provided for supplying lubricant to the spiral groove. This structure provides that rotation of the spindle causes the spindle bearing surface to move against the flat and over the spiral groove of the cylinder bearing surface pushing the lubricant through the spiral groove and carrying it over and across the flat of the spindle bearing surface. The spiral groove may comprises a first and a second spiral groove with the first spiral groove spiraling in a first direction and the second spiral groove spiraling in a second direction opposite to the first direction. The first and second spiral grooves begin substantially centrally of the bearing surface where a lubricant supply is located. Rotation of the spindle bearing acts to assist in moving the lubricant over the flat, through the first and second spiral grooves and out the end surfaces of the cylinder.
The first and second spiral grooves are cut to about seven threads per inch and to about 0.030 inch R and 0.025 inch in depth.